Canto 2 -
Ayodhyā-kāṇḍa
Chapter 8: The Conversation Between Kaikeyī and Mantharā
Text 2.8.17

सा त्वमभ्युदये प्राप्ते वर्तमाने च मन्थरे।
भविष्यति च कल्याणे किमर्थं परितप्यसे॥

sā tvam abhyudaye prāpte vartamāne ca manthare
bhaviṣyati ca kalyāṇe kim arthaṁ paritapyase

tvam = you; abhyudaye = when this appropriate festivity; prāpte vartamāne ca = is at hand; manthare = Mantharā; bhaviṣyati = is to take place in the future; ca = and; kalyāṇe = an auspicious event; kim artham = why; paritapyase = are so pained.

Mantharā, when this appropriate festivity is at hand and an auspicious event is to take place in the future, why are you so pained?

The appropriate festivity is the auspicious coronation of Rāma. The auspicious event to take place in the future is the coronation of Bharata [by Rāma].